Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds genuinely useful context beyond that: the platform enum mapping (TWILIO=SMS, FACEBOOK=Messenger), hidden/archived flags, the pagination loop via next_cursor, and the GraphQL query name. Absent rate-limit or ordering details keeps it from a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single dense sentence plus a short routing clause and pointer to the GraphQL query — every fragment earns its place, and the most important information (what it lists, how to page, where to go next) is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, yet the description enumerates the returned fields, explains pagination, and decodes the platform enum, which is exactly what an agent needs to interpret results. Nothing material for calling this read-only list tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both parameters (after, page_size) are already fully documented with limits and defaults. The description only restates the pagination flow ('Page with next_cursor') without adding syntax or edge-case behavior, so the schema is doing the heavy lifting — baseline 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('List text conversations (the inbox)') and enumerates the returned fields (id, participant number, platform, flags, creation date, contact). It also names the underlying GraphQL query and points to superphone_get_conversation for detail, so it is clearly separable from its sibling.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly routes to the alternative: 'Read the messages of one with superphone_get_conversation,' which tells the agent when to switch tools. No explicit exclusions or conditions (e.g., filtering/preconditions) are given, keeping it below a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.